Geographic Range

Lepisosteus osseus is widely distributed throughout the eastern United States. L. osseus can be found along the eastern seaboard from the Delaware River, N.J. to central Florida and in the upper Midwest in the St. Lawrence River, Quebec and all of the Great Lakes except Superior. It lives throughout the entire Mississippi River basin and can be found as far south as the Rio Grande drainages of Texas and Mexico (Page and Burr, 1991).

Habitat

L. osseus live in a variety of lowland habitats, preferring sluggish areas of larger rivers, lakes, reservoirs and estuaries. They can live in brackish water and are common in the deeper bayous along the Gulf Coast (Goodyear, 1967). L. osseus can tolerate high water temperatures and can often be found near the water surface on warm days or nights (Becker, 1983).

Physical Description

Longnose gar have long, narrow snouts more than twice as long as the rest of the head and they have abundant, sharp, villiform teeth. Mature L. osseus are olive brown in color with a white belly. Dark spots can be found on the median fins and, in individuals from clear water, on the body. Young L. osseus have a narrow brown stripe along their back and a broad dark brown strip along their sides (Page and Burr, 1991; Becker, 1983). The dorsal and anal fins of the longnose gar are located far back on the body, which is encased in a heavy armor of interlocking, rhomboid, ganoid scales (Ross, 2001).

Development

L. osseus eggs typically hatch 3-9 days after they have been laid and the larvae are approximately 8-10 mm long at hatching (Yeager and Bryant, 1983; Becker, 1983). The yolk sac is absorbed at approximately 12 mm TL and fins form around 30 mm TL (Simon and Wallus, 1989). Early-stage L. osseus larvae (sac-fry) are relatively inactive and possess an adhesive structure at the tip of the snout by which they attach to objects in the water. By 10 to 11 days after hatching, L. osseus are 18-20 mm long. Young longnose gar grow rapidly and studies have shown that they can gain 3.2 mm and 1.8 grams per day, when maintained in aquaria with an unlimited food supply (Riggs and Moore, 1960). Male longnose gar will typically mature at three to four years of age while females do not mature until six years (Ross, 2001).

Reproduction

During the mating process as many as 15 males may approach the female. If she is ready, she will lead them in an elliptical pattern for up to 15 minutes prior to spawning. Once over the spawning bed, the males will nudge the female with the ends of their snouts in the pectoral, lateral, and ventro-lateral areas. During this phase, frequent surfacing and gulping take place. Ultimately, the spawning group will position itself at one place with heads down and snouts very close to the bottom. Rapid and violent quivering follows as the sperm and eggs are released (Haase, 1969).

Spawning occurs in the spring and summer for L. osseus. In rivers, longnose gar make upstream spawning runs during the spring period of high water, then move downstream into larger pools. They have also been seen spawning in open, wind-exposed areas over rocks as well as gravelly, weedy sites. Spawning takes place in shallow water resulting in the backs of the fish sometimes being exposed. Often, more than one male will attend to the larger female during spawning. She will not release all of her eggs at the same time. Once shed, the eggs become very sticky and adhere to solid objects on the substrate (Ross, 2001). Females produce about 30,000 eggs per year; 77,000 eggs were once recorded in a female observed in Tennessee (Etnier and Starnes, 1993).

L. osseus provide no parental care. Research has shown frequent occurrences of the longnose gar laying eggs in smallmouth bass nests, where the male bass guarding the nest provides protection for the young gar in addition to its own young (Goff, 1984).

Parental Investment

pre-fertilization

provisioning

Lifespan/Longevity

Longnose gar can be aged by annular marks on their branchiostegal rays. Female L. osseus grow more quickly and live longer than males. They are capable of living well beyond 17 years and some have reached 22 years in the wild. In captivity, female L. osseus have lived up to 30 years (Ross, 2001). Male longnose gar typically do not live longer than 11 years in the wild. A study by Netsch and Witt (1962) in Missouri did not find any males older than 17 years of age.

Behavior

A unique behavior of the longnose gar is its ability to survive in low-oxygen waters. L. osseus has a highly vascularized swimbladder, which connects to the pharynx by a pneumatic duct, to breath air. Under normal oxygen levels, both aquatic and aerial respiration occurs. However, as oxygen becomes limited, L. osseus will close its gill covers and can survive indefinitely on aerial respiration alone (McCormack, 1967).

Communication and Perception

The communication of L. osseus is not well understood. They are a gregarious fish though, often found in groups of two to five, sometimes along with shortnose gar (Lepisosteus platyrhincus) (Holloway, 1954).

Food Habits

By 10-11 days after hatching, young gar begin feeding on small crustaceans, such as cladocerans and copepods, and insects, including various dipterans such as chironomids. L. osseus quickly switch to a diet of primarily fish. Gars are active night feeders and much of the feeding is surface-oriented (Becker, 1983). They catch their prey sideways in their well-toothed jaws by lying motionless or slowly stalking prey until the smaller fish are within reach. L. osseus slashes its beak from side to side, impaling the prey on its teeth. The prey is then maneuvered into position to be swallowed headfirst (Branson, 1966).

In most studies of adult L. osseus, a variety of species made up a majority of the diet, with the dominant prey changing among locations. Inland silversides were particularly common prey of juvenile gar in Lake Texoma, making up 84% of the diet, with gamefishes accounting for less than 1% of the diet (Eschelle, 1968). In Florida, the diet was comprised mainly of fishes, with gizzard shad, bullhead catfish, and small bluegill particularly common (Crumpton, 1971). In Missouri, Netsch (1964) found that fishes made up 98% of the diet with shiners being the most common prey. In some lakes, adult longnose gar may consume large numbers of sunfishes. Menhaden are a major food source along coasts where L. osseus move towards the mouth of bayous into higher salinity waters in the afternoon and evening to find this more prevalent prey. Longnose gar will then move back up the bayous, into the lower salinity waters in the morning (Ross, 2001).

Predation

As previously mentioned, L. osseus are encased in a heavy armor of interlocking, rhomboid, ganoid scales. The ganoid scales are composed of two layers, an outer layer of ganoin and an inner layer of isopedine, both of which are penetrated by blood vessels. As a result of this armor, the longnose gar has no major predators. There have been occurrences of longnose gars being attacked by alligators, but research suggests that these may have been opportunistic events (McCormack, 1967).

Known Predators

American alligators (Alligator mississipiensis)

Ecosystem Roles

The general perception of L. osseus is that it is a nuisance or “trash” fish. However, all species of gar serve as hosts to the parasitic young (glochidia) of the yellow sandshell, a freshwater mussel. Without gar, this mussel would disappear unless it was maintained by artificial means (Becker, 1983).

Economic Importance for Humans: Positive

L. osseus, although palatable, are not particularly popular or sought after by anglers. There is a commercial fishery for longnose gar in Arkansas though (Ross, 2001). Consideration has been given to gars as a possible aid in controlling overpopulation of sunfish and yellow perch as well (Niemuth et al., 1959). Additionally, gar skins have been used to a small extent for covering picture frames, purses, and the like. The gar scales are very hard and take on a fine polish (Forbes & Richardson, 1920).

Economic Importance for Humans: Negative

L. osseus have historically been perceived as detrimental to game species, such that gar management has emphasized removing the species from aquatic environments (Johnson and Nolte, 1997). In addition, the longnose gar has a propensity for becoming entangled in nets and is considered a pest by commercial fisherman (Ross, 2001). Forbes and Richardson (1920) stated: “it is a wholly worthless and destructive nuisance in relation to mankind. It has, in fact, all the vices and none of the virtues of a predaceous fish” (Netsch and Witt, 1962).

Conservation Status

L. osseus is not listed on the IUCN list, the United States Endangered Species Act list or the CITES appendices.

Other Comments

The large, greenish eggs of L. osseus are toxic to humans, other mammals and birds and should not be eaten (Netsch and Witt, 1962). Historically, the heavy rhomboid scales of the gar were often used by local Indians for arrow points, ornaments, and other instruments (Suttkus, 1963).

Contributors

William Fink (editor), University of Michigan-Ann Arbor.

Bruce Rudy (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

estuarine

an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

freshwater

mainly lives in water that is not salty.

intertidal or littoral

the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

piscivore

an animal that mainly eats fish

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

Goodyear, C. 1967. Feeding habits of three species of gars, *Lepisosteus*, along the Mississippi Gulf Coast. Transactions of the American Fisheries Society,, 96: 296-300.

Haase, B. 1969. An ecological life history of the longnose gar, *Lepisosteus osseus* (Linnaeus), in Lake Mendota and several other lakes of southern Wisconsin. Madison: Doctoral dissertation. University of Wisconsin.

Holloway, A. 1954. Notes on the life history and management of the shortnose and longnose gars in Florida waters. Journal of Wildlife Management,, 18(4): 438-449.

Ross, S. 2001. The Inland Fishes of Mississippi. Jackson: University Press of Mississippi.

Simon, T., R. Wallus. 1989. Contributions to the early life histories of gar (*Actinopterygii: Lepisosteidae*) in the Ohio and Tennessee river basins with emphasis on larval development. Transactions of the Kentucky Academy of Science,, 50: 59-74.

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This material is based upon work supported by the
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Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.